Vortex valves

ABSTRACT

A vortex valve flow control includes a housing defining a vortex chamber having an inlet for introducing a liquid into the vortex chamber in a manner to promote swirl and an outlet in one axial end of the vortex chamber. The peripheral wall of the of the vortex chamber, which is situated between the two end walls and surrounds the longitudinal axis of the vortex chamber, has a cylindrical cross-section. The distance between the end walls of the vortex chamber is no more larger than the diameter of the vortex chamber. A mounting device mounts a vortex valve flow control in a drainage gully whereby the outlet of the vortex valve communicates with the outlet from the gully. The mounting device includes a first element being securable to an end wall about the outlet opening and a second element mountable in or adjacent the outlet opening of the gully.

This invention relates to vortex valve flow controls.

A vortex valve flow control is a device for controlling fluid flow by ahydraulic effect without requiring moving parts. Such devices have avortex chamber provided with an outlet at one axial end and an inletarranged to cause swirl in the chamber when a certain critical flow hasbeen attained. In use, the inlet communicates with a body of water whichexerts a pressure head on the liquid entering the vortex chamber. Air isentrained in the liquid drawn through the valve so that, when vortexflow has been established, a central air core exists. U.S. Pat. No.4,206,783 discloses a vortex valve having a conical vortex chamber witha tangential inlet and an outlet disposed at the narrower end of thechamber. Also known are short vortex valves of which the cross-sectionalconfiguration of the vortex chamber is a logarithmic spiral extendingthe full length of its longitudinal axis to the outlet. At low flowrates, water entering through the inlet of a vortex valve passes throughthe vortex chamber to the outlet with substantially no pressure drop andthe valve can be considered to be open. However, at high flow rates,water enters through the inlet with enough energy to create a vortex inthe vortex chamber which results in a considerable pressure drop betweenthe inlet and the outlet and may greatly restrict flow through theoutlet, or even substantially cut it off altogether. Thus the valveserves to limit the rate of flow through it automatically. Vortex valvescan be used, for example, to control the flow of storm water in sewers,to ensure that equipment downstream of the valve is not overloadedduring periods of heavy rainfall.

The flow characteristics of a vortex valve flow control (once a vortexhas been initiated in the vortex chamber thereof) are dependent on anumber of factors including the area of the outlet (A) and the head (H)of fluid upstream of the device. A reasonable approximation of therelationship between the flow (Q) through a vortex valve flow controland the area of the outlet (A) and head (H) is given by the equation:

Q=C_(d)·A{square root over (()}2gH)

where C_(d) is a coefficient of discharge which is dependent upon thetype of vortex valve under consideration, and g is the gravity constant.

Before initiation of the vortex, the rate of flow of fluid through thedevice is directly dependent upon the head (H) and the area (A) of theoutlet. In the “pre-initiation” zone (i.e shortly before initiation),the flow actually decreases somewhat for a small increase in head,before increasing again at initiation at a slower rate than before. Thisgives rise to what is termed a “pre-initiation bulge” during which thecharacteristics of the vortex valve are such that it permits a higherrate of flow for a given pressure head than one would expect from adirect extrapolation back towards the origin of the curve at high headsafter initiation. In some circumstances, it is desirable to reduce oreven eliminate the pre-initiation bulge.

The configuration and dimensions of a vortex valve determine its flowcharacteristics, namely its coefficient of discharge (C_(d)), the extentof pre-initiation bulge and the head required to initiate the vortex.

Until the present invention, it had been the experience that an increasein the dimensions of the outlet from the vortex chamber would cause achange in the coefficient of discharge; thus, in order to maintain aconstant coefficient of discharge within a range of vortex valve flowcontrols having the same overall general configuration, but differentoutlet opening dimensions, it has previously been necessary to varyother dimensions of the device, including the dimensions of the inletand the overall dimension (typically the dimension of the longitudinalaxis and the diameter) of the vortex chamber itself. As a consequence,it has been necessary for suppliers of vortex valves to manufacture andkeep stocks of a wide range of sizes of vortex valve.

The present invention is based on the finding that a vortex valve can bedesigned with a coefficient of discharge which remains constant over awide range of outlet dimensions, the only requirement being acorresponding adjustment in the dimensions of the inlet opening. Thismakes it possible for a supplier of vortex valves to manufacture andstock a single vortex valve “precursor” from which a range of vortexvalve flow controls with the same (or substantially the same)coefficient of discharge, but with different outlet opening dimensions,may be constructed. This requires the supplier only to form theappropriate outlet opening and inlet opening in the end wall andperipheral wall respectively of the vortex chamber to create a suitablevortex valve flow control to meet a customer's needs. There areconsiderable practical as well as economic advantages associated withthe ability of a supplier to be able to meet its customers requirementsin this way, not least the economic advantage of not having to“customise” each vortex valve to a customer's order.

According to a first aspect of the present invention, there is provideda vortex valve flow control comprising a housing defining a vortexchamber having an inlet for introducing a liquid into the vortex chamberin a manner to promote swirl and an outlet in one axial end of thevortex chamber, characterised in that:

the peripheral wall of the vortex chamber which is situated between thetwo end walls and surrounds the longitudinal axis of the vortex chamberhas a cylindrical cross-section; and

the distance between the end walls (as measured at the axis of the flowcontrol) of the vortex chamber is no larger than the diameter of thevortex chamber.

In a preferred embodiment of the vortex valve in accordance with thisaspect of the invention, the inlet is an inlet means in the form of aninlet conduit or pipe which is open at both ends, the end thereof whichintersects the peripheral wall of the vortex chamber constituting theinlet opening into the vortex chamber.

A further preferred feature is that the intersection or junction betweeneach end wall of the vortex chamber and the cylindrical peripheral wallshould take the form of a circumferentially extending concave portion(when viewed from inside the vortex chamber) having a radius ofcurvature which is typically less than 25% of the diameter of the vortexchamber.

The Peripheral Wall of the Vortex Chamber

The peripheral wall of the vortex chamber which is situated between thetwo end walls and surrounds the longitudinal axis of the vortex chamberhas a cylindrical cross-section, that is to say it should have aconstant cross-section along its length.

The peripheral wall of the vortex chamber is preferably of circularcylindrical form, although other cross-sectional forms, such as oblongor elliptical forms are also contemplated

The Inlet Means

The inlet means comprises a conduit or pipe which serves to directliquid flow to the vortex chamber in a manner to promote swirl of theliquid in the vortex chamber when a predetermined pressure head isreached. The inlet conduit preferably has a circular cross section andis preferably arranged to direct liquid flow tangentially into thevortex chamber. As a consequence of its tangential abutment to theperipheral wall of the vortex chamber, the actual inlet opening in theperipheral wall of the vortex chamber is not circular, but rather has anelliptical form which corresponds to the shape of the end of the inletconduit at its intersection with the peripheral wall. The length of thetubular conduit is not critical, but typically will be of the order ofthe inlet or outlet diameter.

The End Walls of the Vortex Chamber

As stated above, the distance between the end walls (as measured at theaxis of the flow control) of the vortex chamber is no larger than thediameter of the vortex chamber. Preferably, this distance is no morethan 60% of the diameter of the vortex chamber. The depth of the vortexchamber, i.e. its dimension measured along its axis, is thus relativelyshort compared with its diameter.

The end walls of the vortex chamber may be planar and parallel with eachother. Alternatively, each end wall may take a concave form (as viewedfrom the inside of the vortex chamber), preferably with a relativelylarge radius of curvature which may, for example, be approximately thesame as the diameter of the vortex chamber or may be greater than thediameter of the vortex chamber. A combination of one planar wall and oneconcave wall is also contemplated.

The outlet opening is disposed axially in one of the end walls of thevortex chamber.

The Junction Between the End and Peripheral Walls

Where the end walls of the vortex chamber are planar, the radius ofcurvature of the circumferential concave portion is typically less than5% of the diameter of the vortex chamber. Where the end walls of thevortex chamber are concave, the radius of curvature of thecircumferential concave portion is typically between 5% and 25% of thediameter of the vortex chamber.

Construction of Vortex Valves of the Invention

The vortex valve housing may conveniently be constructed from twoidentical shells which are joined together along a circumferentialcentre line to form the desired vortex chamber. Where the vortex valveis to be formed of a metal, such as steel, the two halves may be weldedtogether. Where they are made from a plastics material, a suitabletechnique for joining the two plastic shells should be employed. Thiscould either be by fusion butt welding or another appropriate processfor the manufacture of plastic shaped products of similar construction.

Pre-formed housings without an inlet means and outlet opening may bemanufactured in bulk and stored ready for a finishing process in whichthe desired outlet opening and corresponding inlet means are added.Alternatively, the pre-formed housing may be constructed with an axialoversize outlet opening which, when the finished article is to beproduced, needs only to be throttled down using a suitable plate havingan opening of the correct size in it which is secured axially over theoversize opening.

The inlet means is secured to the vortex chamber housing by suitableinter-penetration methods.

In addition, the vortex valve of the present invention may be providedwith a novel mounting means for mounting the vortex valve in position ina drainage gully so that its outlet communicates with the outlet fromthe gully, which gully outlet normally takes the form of a circularopening in a side wall of the gully which in turn communicates with adrainage pipe extending away from the gully. This novel mounting means(which is an independent aspect of the present invention) enables thevortex valve flow control to be lifted clear of the drainage outlet withrelative ease to permit drain-down of the gully and cleaning to takeplace.

The essential characteristic of this novel mounting means is that itcomprises first and second elements, the first element being securableto the end wall of the vortex valve housing about the outlet openingthereof and the second element being mountable in or adjacent the outletopening of the gully. Alternatively, one or other or both of the firstand second elements may be formed integrally with the vortex valvehousing and the region of the outlet opening of the gully respectively.

One of the said elements preferably defines a slot which is capable ofslidably receiving and locating a suitably shaped head portion of theother of said elements. When located together, the first and secondportions form a combined mounting which allows the outlet opening of thevortex chamber to communicate with the outlet opening of the gully in asubstantially liquid tight manner.

The slot defined in one of the said elements is preferably orientedvertically and may be in the shape of a truncated wedge, the thin end ofthe wedge being uppermost, and the wider edge of the wedge beinglowermost and serving as the mouth of the slot for slidably receivingthe head portion of the second element of the mounting means.

Preferably, the slotted element is securable to (or formed as part of)the vortex valve housing, and the other element, comprising a wedgeshaped head portion, is mounted to a spigot which is a push-fit in theoutlet opening of the gully.

For a better understanding of the present invention, and to show how itmay be brought into effect, reference will now be made, by way ofexample, to the accompanying drawings, in which:

FIG. 1a is a view toward one end of a vortex valve flow control inaccordance with the present invention and

FIG. 1b is a view in the direction I—I of FIG. 1a;

FIG. 2a is a view towards one end of another vortex valve flow controlin accordance with the present invention and

FIG. 2b is a view in the direction II—II of FIG. 2a;

FIG. 3a is a view towards one end of a third embodiment of a vortexvalve flow control in accordance with the present invention and

FIG. 3b is a view in the direction III—III in 3 a;

FIG. 4a is a perspective view from one side towards a vortex valvehaving one element of a mounting device in accordance with anotheraspect of the present invention and

FIG. 4b is the other part of the mounting device corresponding to thatin FIG. 4a;

FIGS. 5a and 5 b show a perspective view and a side view respectively ofthe slotted element of the mounting device of the present invention; and

FIGS. 6a and 6 b show a perspective view and a side view of anotherembodiment of the slotted element of the mounting device in accordancewith the present invention.

FIGS. 1a and 1 b; FIGS. 2a and 2 b; and FIGS. 3a and 3 b illustratedifferent embodiments of a vortex valve in accordance with the presentinvention. All three embodiments will be defined described together, theonly difference between the three being the curvature (or absence ofcurvature) in the end walls of the vortex valve flow control and thedimensions of the inlet/outlet.

The vortex valve 1 shown in FIGS. 1-3 comprises a housing wall 2 whichdefines a vortex chamber 3 into which liquid may be introduced via inletmeans 4 in a manner to promote swirl within the vortex chamber 3.

The inlet means 4 comprises an inlet pipe 5 having an opening 6 intowhich liquid may flow and an opening 7 at the intersection with thevortex chamber 3. Inlet means 4 is oriented tangentially to the vortexchamber 3. Disposed axially of the vortex chamber 3 is an outlet opening8 through which liquid may exit the vortex chamber 3. In the embodimentsshown in FIGS. 1-3, the diameter of the inlet 6 and the outlet 8 are thesame, although they may be different in different arrangements of vortexvalves in accordance with the invention. The vortex chamber 1 has aperipheral wall 10 which is situated between end walls 11 and 12. Theperipheral wall 10 surrounds the longitudinal axis of the vortex chamber3 and is preferably of circular cylindrical form, i.e. it has a constantcircular cross-section along its length. This section of the vortexchamber is relatively short compared to the diameter of the vortexchamber.

At the intersection or junction between each end wall 11, 12 and thecylindrical peripheral wall 10 there is a circumferentially extendingconcave (when viewed from inside the vortex chamber) portion 15 and 15′.

In the embodiment of FIGS. 1a and 1 b, each end wall, 12 of the vortexvalve 1 has a concave, or dished, form. In the embodiment shown in FIG.2a and 2 b, the radius of curvature is somewhat less than the radius ofcurvature in figure 1a and 1 b. In the embodiment shown in FIG. 3a and 3b, the end walls 11 and 12 are plainer, and parallel to each other.

The vortex valve shown in FIGS. 1-3 is well suited to a fabricationmethod in which the vortex valve housing is formed in two shells whichmay be joined together using a suitable technique, such as welding. Italso makes possible the mass production of vortex valves using plasticmaterials, such as high density polyethylene, polypropylene, PVC orother plastics material used for drainage products.

It has been found that vortex valve flow controls in accordance with thepresent invention as illustrated in FIGS. 1-3 possess the desirablecharacteristic that, when the dimension of the outlet is varied, andwith a corresponding variation in the diameter of the inlet to thevortex chamber, the coefficient of discharge remains substantiallyconstant.

FIGS. 4a and 4 b illustrate a novel mounting means for a vortex valveflow control. This novel mounting means enables a vortex valve flowcontrol to be mounted in a drainage gully in such a way that it iseasily able to be lifted clear of the drainage outlet of the gully topermit drain-down of the gully in which the vortex valve is situated,and cleaning to take place.

The mounting means comprises a first element 20 which is secured to anend wall of a vortex valve flow control 21 about the outlet opening 22thereof. The first element 20 comprises a back plate 23 which is securedto the end wall of the vortex valve flow control, for example bysuitable fixing elements 24. This back plate 24 is provided withprojecting sidewall portions 25 each of which has a return flange 26.Sidewalls 25 are each in the shape of a truncated wedge and, togetherwith the return flange 26 define a wedge-shaped slot, the thin end ofwhich is uppermost and the wide end of which faces downwards in use.This slot is capable of receiving and locating a corresponding headportion 30 of a second element 31 of the mounting means as shown in FIG.4b. The second element 31 comprises a hollow spigot 32 which is a pushfit in the outlet opening of a drainage gully. The spigot 32, preferablymade of metal, is welded to a suitable bracket 33, which bracket isprovided with side-portions 34 and return flanges 35. On the front faceof the bracket 33 is provided a high-density plastic intermediate layer36. The shape of the head portion 30 of the second element is such thatit corresponds to the shape of the slot in the first element 20described above. Thus, in use, the outlet spigot 32 is introduced intothe outlet opening of a drainage gully (not shown), with the headportion 30 protruding from. The vortex valve flow control may then belowered onto the head portion 30, for example using handle 40, so thatthe head portion 30 engages and is located in the slot in the firstelement 20. The two parts are dimensioned such that there is asubstantially watertight fit between the two parts, with the highdensity plastic intermediate layer assisting in this respect by allowingfor varying tolerances between the two elements. The front face of thehead element 30 is, of course, provided with a suitable opening (notshown) which is in alignment with the outlet opening of the vortex valveflow control to permit liquid flow from the vortex valve flow controlinto the drainage outlet of the gully.

FIGS. 5a/5 b and 6 a/6 b illustrate two embodiments of the said firstelement in FIG. 4a before attachment to the vortex valve flow controlhousing.

What is claimed is:
 1. A vortex valve flow control comprising a housingdefining a vortex chamber having an inlet for introducing a liquid intothe vortex chamber in a manner to promote swirl and an outlet in oneaxial end of the vortex chamber, wherein: a peripheral wall of thevortex chamber is situated between two end walls and which surrounds thelongitudinal axis of the vortex chamber has a circular cylindricalcross-section; the end walls of the vortex chamber are planar andparallel with each other; and a distance between the end walls asmeasured at the axis of the flow control of the vortex chamber is nomore than 60% of the diameter of the vortex chambe.r
 2. A vortex valveflow control according to claim 1, wherein the inlet is an inlet meansin the form of an inlet conduit or pipe which is open at both ends, theend thereof which intersects the peripheral wall of the vortex chamberconstituting the inlet opening into the vortex chamber.
 3. A vortexvalve flow control according to claim 1, wherein the intersectionbetween each end wall of the vortex chamber and the cylindricalperipheral wall takes the form of a circumferentially extending concaveportion when viewed from inside the vortex chamber having a radius ofcurvature which is typically less than 25% of the diameter of the vortexchamber.
 4. A mounting means for mounting a vortex valve flow control ina drainage gully whereby an outlet of the vortex valve communicates withan outlet from the gully, comprising first and second elements, thefirst element being securable to an end wall of a vortex valve housingabout an outlet opening thereof and the second element being mountablein or adjacent the outlet of the gully, wherein one of the said elementsdefines a slot which is capable of slidably receiving and locating ahead portion of the other of said elements such that the two elementsare able to cooperate with each other in a substantially liquid tightmanner.
 5. A mounting means according to claim 4, wherein one or otheror both of the first and second elements is formed integrally with thevortex valve housing and the region of the outlet opening of the gullyrespectively.
 6. A mounting means according to claim 4 wherein the slotdefined in one of the said elements is in the shape of a truncatedwedge, the wider edge of the wedge serving as the mouth of the slot forslidably receiving the head portion of the second element of themounting means.